FarmVille creator Zynga sees big riches in social network platforms, but vendor lock-in means this gold rush may not pan out for independent developers

Today's developers are all too aware of the dangers of vendor lock-in when choosing an application platform. Want to write apps for Apple iOS? Better learn Objective-C and the terms of the iTunes App Store. Android? That'll be Java coupled with Google's online infrastructure. Windows? Get ready to go exclusive with the likes of .Net, Visual Basic, and C#. None of these platforms makes it easy to port software to the others.

Now a new kind of development platform is emerging, one that takes the "walled garden" concept to a whole new level. Social networking sites, which are rapidly supplanting search engines and Webmail services as the home pages of the typical consumer, offer unique new opportunities for developers to tap their vast, interconnected audiences.

It's not hard to see the appeal of these platforms for developers. Facebook claims more than 750 million active users, while Google+ reportedly pulled in 10 million users in just two weeks, despite its status as an invite-only field trial. And as anyone with a Facebook account can attest, social network users love apps. The typical Facebook news feed is awash with game status updates, surveys, quizzes, ratings, and tie-ins to other services. Adonomics values the total Facebook apps market at $269 million.

But how good an opportunity are social networking apps really? If the thought of being rejected from the iTunes Store rankles, consider how much more control Facebook wields over its ecosystem. Platform functions can be withdrawn, terms of business can change, and access to data can be limited or curtailed, all at Facebook's sole discretion. Any one of these changes could pull the rug out from under a well-conceived business plan. It's enough to make you wonder: Are social networking platforms worth the risk?

Facebook holds all the cardsThe ultimate litmus test is already under way. Zynga, developer of the popular Facebook games FarmVille, FrontierVille, and Mafia Wars, among others, is a current darling among the latest round of high-tech IPOs. In its pre-IPO filing with the SEC, Zynga revealed it earned almost $600 million in revenue from its games in 2010, and $235 million in the first three months of 2011 alone.

More startling, however, the game maker admitted that it generated "substantially all" of its players and revenue through Facebook. Ties between the two companies are so close, in fact, that Business Insider goes so far as to say Facebook basically owns Zynga.

Further examination of Zynga's amended SEC filings reveals that its relationship with Facebook does indeed seem unusual. For one thing, as part of its dealings with the social network, Zynga has agreed to have Facebook be the exclusive social platform for its games, both on the Web and on mobile devices. In addition, every Zynga game player must have an active Facebook account.